The present invention relates to an apparatus having an optical structure and ridges connecting the optical structure to a supporting structure, wherein the optical structure is able to perform a movement with regard to a reference plane, and the invention also describes possible adjustments for the apparatus.
Optical structures made of curable material, as are known, for example, from DE 102009055080 A1, change their characteristics with varying environmental temperatures. Thus, a polymer lens changes its extension with varying temperature, such that the refractive index and the curvature of the optical lens are also changed. This can have the effect that an optical device, such as a camera or a projector, provides a varying image capturing and/or image reproduction quality.
For compensating a varying image reproduction and/or image capturing quality, lenses and/or lens groups used in optical equipment are readjusted for compensating a thermally induced variation of a focal length of the optical equipment. For this, actuators, such as moving coil drives, piezo motor drives or other motor drives are used. Also, liquid lenses are used which allow a variation of the lens curvature. However, these methods necessitate active adjustment of the focal length of the optical system.
As a result of variations in the manufacturing process of optical components, the parameters of the components, in particular the focal length of the lenses, vary. If the components are joined to more complex structures together with further components, the target parameters of the assembly, for example an objective, might not be obtained. In order to ensure optimum functionality, the components have to be readjusted after joining in order to ensure optimum orientation of the individual components and hence compensation of inaccuracies occurring as a consequence of production and joining tolerances. The main target of adjustment is, for example, optimum orientation of the image plane of a lens or a lens stack with regard to a predetermined image plane, wherein at least one optoelectronic image converter, a so-called imager, resides.
Lenses or lens groups, such as objectives, are cased in one or several housing parts, among others including an external thread. A holder having a corresponding internal thread can be inserted in one or several housing parts, wherein a specific distance, mostly an optimum focal position, is adjusted. After the adjustment has been performed, the position is possibly fixed, for example by an adhesive which can be implemented in a UV-curable manner. In this way, the overall optical structure is adjusted via additional apparatuses that are to be introduced specifically and that are implemented exclusively for this step.
For realizing the autofocus function, among others, voice coil motors are used. The same consist of many individual parts and cannot be produced in wafer level technology.